ethers

ETHERS(3)                BSD Library Functions Manual                ETHERS(3)

NAME
     ether_aton, ether_ntoa, ether_addr, ether_ntohost, ether_hostton,
     ether_line - get ethers entry

SYNOPSIS
     #include <netinet/if_ether.h>

     char *
     ether_ntoa(struct ether_addr *e);

     struct ether_addr *
     ether_aton(char *s);

     int
     ether_ntohost(char *hostname, struct ether_addr *e);

     int
     ether_hostton(char *hostname, struct ether_addr *e);

     int
     ether_line(char *l, struct ether_addr *e, char *hostname);

DESCRIPTION
     Ethernet addresses are represented by the following structure:

           struct ether_addr {
                   u_int8_t  ether_addr_octet[6];
           };

     The ether_ntoa() function converts this structure into an ASCII string of
     the form ``xx:xx:xx:xx:xx:xx'', consisting of 6 hexadecimal numbers sepa-
     rated by colons.  It returns a pointer to a static buffer that is reused
     for each call.  The ether_aton() converts an ASCII string of the same
     form and to a structure containing the 6 octets of the address.  It
     returns a pointer to a static structure that is reused for each call.

     The ether_ntohost() and ether_hostton() functions interrogate the
     database mapping host names to Ethernet addresses, /etc/ethers.  The
     ether_ntohost() function looks up the given Ethernet address and writes
     the associated host name into the character buffer passed.  This buffer
     should be MAXHOSTNAMELEN characters in size.  The ether_hostton() func-
     tion looks up the given host name and writes the associated Ethernet
     address into the structure passed.  Both functions return zero if they
     find the requested host name or address, and -1 if not.

     Each call reads /etc/ethers from the beginning; if a '+' appears alone on
     a line in the file, then ether_hostton() will consult the ethers.byname
     YP map, and ether_ntohost() will consult the ethers.byaddr YP map.

     The ether_line() function parses a line from the /etc/ethers file and
     fills in the passed struct ether_addr and character buffer with the Eth-
     ernet address and host name on the line.  It returns zero if the line was
     successfully parsed and -1 if not.  The character buffer should be
     MAXHOSTNAMELEN characters in size.

FILES
     /etc/ethers

SEE ALSO
     ethers(5)

HISTORY
     The ether_ntoa(), ether_aton(), ether_ntohost(), ether_hostton(), and
     ether_line() functions were adopted from SunOS and appeared in NetBSD 0.9
     b.

BUGS
     The data space used by these functions is static; if future use requires
     the data, it should be copied before any subsequent calls to these func-
     tions overwrite it.

BSD                            December 16, 1993                           BSD